Fasteners such as nails and staples are commonly used in projects ranging from crafts to building construction. While manually driving such fasteners into a work piece is effective, a user may quickly become fatigued when involved in projects requiring a large number of fasteners and/or large fasteners to be driven into a work piece. Moreover, proper driving of larger fasteners into a work piece frequently requires more than a single impact from a manual tool.
In response to the shortcomings of manual driving tools, power-assisted devices for driving fasteners into work pieces have been developed. Contractors and homeowners commonly use such devices for driving fasteners ranging from brad nails used in small projects to common nails which are used in framing and other construction projects. Compressed air has been traditionally used to provide power for the power-assisted (pneumatic) devices. However, other power sources have also been used, such as DC motors.
Various safety features have been incorporated into pneumatic and other power nailers. One such device is commonly referred to as a work contact element (WCE). A WCE is incorporated into nail gun designs to prevent unintentional firing of the nail gun. A WCE is typically a spring loaded mechanism which protrudes outwardly from the nose portion of the nail gun from which a nail is driven. In operation, the WCE is pressed against a work piece into which a nail is to be driven. As the WCE is pressed against the work piece, the WCE compresses the spring and generates an axial movement which is transmitted to a trigger assembly via an extension member which links the WCE and the trigger assembly. The axial movement is used to reconfigure a safety device, which is typically a trigger disabling mechanism, so as to enable initiation of a firing sequence with the trigger of the nail gun.
The WCE is typically provided as relatively thin but rigid member such as a wireform or a stamped metal part. During normal operation, the WCE experiences only minimal impact forces as it is pressed against a workpiece in order to release the trigger disabling mechanism. These normal operating forces do not typically result in damage to the WCE. Instead, the WCE is sufficiently robust to absorb normal operating forces and serve its purpose over the life of the tool. However, in some situations, the WCE may experience high impact events where high impact forces are imparted to the WCE, such as when the tool is dropped by the user.
Because of the geometry of the WCE, it may bend, deform or experience other damage when the WCE is exposed to high impact forces. Depending on the severity of the impact force, the damage to the WCE may result in a tool that is unusable. In these situations, the WCE may need to be replaced to allow the tool to return to normal operation. However, the arrangement of the WCE and rigidly connected extension member may make it difficult to easily replace the WCE in the tool.
In view of the foregoing, it would be advantageous to provide a WCE that is capable of withstanding relatively high impact forces. It would also be advantageous if the WCE could be easily replaced in the event of any damage to the WCE.